Sky watchers, it is time to look up once again, and watch the moon very, very carefully. A penumbral lunar eclipse will occur early Wednesday morning, but it will be subtle.

Unlike a total lunar eclipse, when the moon passes behind the dark center of the earth's shadow, a penumbral lunar eclipse occurs when the moon passes through the hazy outer edge of the earth's shadow, called the penumbra.

During a penumbral eclipse, the moon doesn't so much black out completely as darken subtly, but noticeably, if you are paying attention.

It may not be dramatic, but if you see it, it's like sharing a secret with other sky gazers around the planet.

If you live on the West Coast you have a pretty good chance of catching this lunar eclipse, if you're willing to drag yourself out of bed from 4:15 a.m. PST when it begins, to 6:15 a.m., when the eclipse peaks -- meaning, the biggest portion of the moon will be eclipsed by Earth's penumbra.

If you are not on the West Coast, or if you can't find the moon because it is too cloudy, or if you just don't want to go outside at that time of the morning, you can always watch this subtle lunar eclipse online.

Slooh Space Camera is planning to broadcast the penumbral lunar eclipse live on its website, using footage from a telescope in Hawaii.

[For the record, 9:25 a.m. Nov. 28: An earlier version of this article stated that during a lunar eclipse the earth passes through the earth's shadow. That was a typing mistake, and it has been corrected.]